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1.
BMJ Glob Health ; 7(8)2022 08.
Article in English | MEDLINE | ID: covidwho-2001824

ABSTRACT

INTRODUCTION: Estimating COVID-19 cumulative incidence in Africa remains problematic due to challenges in contact tracing, routine surveillance systems and laboratory testing capacities and strategies. We undertook a meta-analysis of population-based seroprevalence studies to estimate SARS-CoV-2 seroprevalence in Africa to inform evidence-based decision making on public health and social measures (PHSM) and vaccine strategy. METHODS: We searched for seroprevalence studies conducted in Africa published 1 January 2020-30 December 2021 in Medline, Embase, Web of Science and Europe PMC (preprints), grey literature, media releases and early results from WHO Unity studies. All studies were screened, extracted, assessed for risk of bias and evaluated for alignment with the WHO Unity seroprevalence protocol. We conducted descriptive analyses of seroprevalence and meta-analysed seroprevalence differences by demographic groups, place and time. We estimated the extent of undetected infections by comparing seroprevalence and cumulative incidence of confirmed cases reported to WHO. PROSPERO: CRD42020183634. RESULTS: We identified 56 full texts or early results, reporting 153 distinct seroprevalence studies in Africa. Of these, 97 (63%) were low/moderate risk of bias studies. SARS-CoV-2 seroprevalence rose from 3.0% (95% CI 1.0% to 9.2%) in April-June 2020 to 65.1% (95% CI 56.3% to 73.0%) in July-September 2021. The ratios of seroprevalence from infection to cumulative incidence of confirmed cases was large (overall: 100:1, ranging from 18:1 to 954:1) and steady over time. Seroprevalence was highly heterogeneous both within countries-urban versus rural (lower seroprevalence for rural geographic areas), children versus adults (children aged 0-9 years had the lowest seroprevalence)-and between countries and African subregions. CONCLUSION: We report high seroprevalence in Africa suggesting greater population exposure to SARS-CoV-2 and potential protection against COVID-19 severe disease than indicated by surveillance data. As seroprevalence was heterogeneous, targeted PHSM and vaccination strategies need to be tailored to local epidemiological situations.


Subject(s)
COVID-19 , Adult , Africa/epidemiology , COVID-19/epidemiology , Child , Europe , Humans , SARS-CoV-2 , Seroepidemiologic Studies
2.
Euro Surveill ; 27(30)2022 07.
Article in English | MEDLINE | ID: covidwho-1974588

ABSTRACT

By employing a common protocol and data from electronic health registries in Denmark, Navarre (Spain), Norway and Portugal, we estimated vaccine effectiveness (VE) against hospitalisation due to COVID-19 in individuals aged ≥ 65 years old, without previous documented infection, between October 2021 and March 2022. VE was higher in 65-79-year-olds compared with ≥ 80-year-olds and in those who received a booster compared with those who were primary vaccinated. VE remained high (ca 80%) between ≥ 12 and < 24 weeks after the first booster administration, and after Omicron became dominant.


Subject(s)
COVID-19 Vaccines , COVID-19 , Aged , COVID-19/epidemiology , COVID-19/prevention & control , Electronics , Hospitalization , Humans , Pilot Projects , Registries , Vaccine Efficacy
3.
Euro Surveill ; 27(26)2022 06.
Article in English | MEDLINE | ID: covidwho-1923991

ABSTRACT

As the COVID-19 pandemic began in early 2020, primary care influenza sentinel surveillance networks within the Influenza - Monitoring Vaccine Effectiveness in Europe (I-MOVE) consortium rapidly adapted to COVID-19 surveillance. This study maps system adaptations and lessons learned about aligning influenza and COVID-19 surveillance following ECDC / WHO/Europe recommendations and preparing for other diseases possibly emerging in the future. Using a qualitative approach, we describe the adaptations of seven sentinel sites in five European Union countries and the United Kingdom during the first pandemic phase (March-September 2020). Adaptations to sentinel systems were substantial (2/7 sites), moderate (2/7) or minor (3/7 sites). Most adaptations encompassed patient referral and sample collection pathways, laboratory testing and data collection. Strengths included established networks of primary care providers, highly qualified testing laboratories and stakeholder commitments. One challenge was the decreasing number of samples due to altered patient pathways. Lessons learned included flexibility establishing new routines and new laboratory testing. To enable simultaneous sentinel surveillance of influenza and COVID-19, experiences of the sentinel sites and testing infrastructure should be considered. The contradicting aims of rapid case finding and contact tracing, which are needed for control during a pandemic and regular surveillance, should be carefully balanced.


Subject(s)
COVID-19 , Influenza Vaccines , Influenza, Human , COVID-19/epidemiology , Europe/epidemiology , Humans , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Pandemics/prevention & control , Primary Health Care , Sentinel Surveillance
4.
Influenza and Other Respiratory Viruses ; n/a(n/a), 2022.
Article in English | Wiley | ID: covidwho-1895988

ABSTRACT

We aimed to estimate the household secondary infection attack rate (hSAR) of SARS-CoV-2 in investigations aligned with the WHO Unity Studies Household Transmission Investigations (HHTI) protocol. We conducted a systematic review and meta-analysis according to PRISMA 2020 guidelines. We searched Medline, Embase, Web of Science, Scopus and medRxiv/bioRxiv for ?Unity-aligned? First Few X cases (FFX) and HHTIs published 1 December 2019 to 26 July 2021. Standardised early results were shared by WHO Unity Studies collaborators (to 1 October 2021). We used a bespoke tool to assess investigation methodological quality. Values for hSAR and 95% confidence intervals (CIs) were extracted or calculated from crude data. Heterogeneity was assessed by visually inspecting overlap of CIs on forest plots and quantified in meta-analyses. Of 9988 records retrieved, 80 articles (64 from databases;16 provided by Unity Studies collaborators) were retained in the systematic review;62 were included in the primary meta-analysis. hSAR point estimates ranged from 2% to 90% (95% prediction interval: 3%?71%;I2?=?99.7%);I2 values remained >99% in subgroup analyses, indicating high, unexplained heterogeneity and leading to a decision not to report pooled hSAR estimates. FFX and HHTI remain critical epidemiological tools for early and ongoing characterisation of novel infectious pathogens. The large, unexplained variance in hSAR estimates emphasises the need to further support standardisation in planning, conduct and analysis, and for clear and comprehensive reporting of FFX and HHTIs in time and place, to guide evidence-based pandemic preparedness and response efforts for SARS-CoV-2, influenza and future novel respiratory viruses.

5.
Euro Surveill ; 27(21)2022 05.
Article in English | MEDLINE | ID: covidwho-1875327

ABSTRACT

IntroductionIn July and August 2021, the SARS-CoV-2 Delta variant dominated in Europe.AimUsing a multicentre test-negative study, we measured COVID-19 vaccine effectiveness (VE) against symptomatic infection.MethodsIndividuals with COVID-19 or acute respiratory symptoms at primary care/community level in 10 European countries were tested for SARS-CoV-2. We measured complete primary course overall VE by vaccine brand and by time since vaccination.ResultsOverall VE was 74% (95% CI: 69-79), 76% (95% CI: 71-80), 63% (95% CI: 48-75) and 63% (95% CI: 16-83) among those aged 30-44, 45-59, 60-74 and ≥ 75 years, respectively. VE among those aged 30-59 years was 78% (95% CI: 75-81), 66% (95% CI: 58-73), 91% (95% CI: 87-94) and 52% (95% CI: 40-61), for Comirnaty, Vaxzevria, Spikevax and COVID-19 Vaccine Janssen, respectively. VE among people 60 years and older was 67% (95% CI: 52-77), 65% (95% CI: 48-76) and 83% (95% CI: 64-92) for Comirnaty, Vaxzevria and Spikevax, respectively. Comirnaty VE among those aged 30-59 years was 87% (95% CI: 83-89) at 14-29 days and 65% (95% CI: 56-71%) at ≥ 90 days between vaccination and onset of symptoms.ConclusionsVE against symptomatic infection with the SARS-CoV-2 Delta variant varied among brands, ranging from 52% to 91%. While some waning of the vaccine effect may be present (sample size limited this analysis to only Comirnaty), protection was 65% at 90 days or more between vaccination and onset.


Subject(s)
COVID-19 , Influenza Vaccines , Influenza, Human , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Vaccines , Europe/epidemiology , Humans , Influenza, Human/prevention & control , Primary Health Care , SARS-CoV-2 , Vaccination
6.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-332375

ABSTRACT

First Few X cases (FFX) investigations and Household transmission investigations (HHTI) are essential epidemiological tools for early characterisation of novel infectious pathogens and their variants. We aimed to estimate the household secondary infection attack rate (hSAR) of SARS-CoV-2 in investigations aligned with the WHO Unity Studies HHTI protocol. We conducted a systematic review and meta-analysis according to PRISMA 2020 guidelines (PROSPERO registration:CRD42021260065). We searched Medline, Embase, Web of Science, Scopus and medRxiv/bioRxiv for ‘Unity-aligned’ FFX and HHTI published between 1 December 2019 and 26 July 2021. Standardised early results were shared by WHO Unity Studies Collaborators (to 1 October 2021). We used a bespoke tool to assess investigation methodological quality. Values for hSAR and 95% confidence intervals (CIs) were extracted or calculated from crude data. Heterogeneity was assessed by visually inspecting overlap of CIs on forest plots and quantified in meta-analyses. Of 9988 records retrieved, 80 articles (64 from databases;16 provided by WHO Unity Studies collaborators) were retained in the systematic review and 62 were included in the primary meta-analysis. hSAR point estimates ranged from 2%–90% (95% prediction interval: 3%–71%;I 2 =99.7%);I 2 values remained >99% in subgroup analyses, indicating high, unexplained heterogeneity and leading to a decision not to report pooled hSAR estimates. The large, unexplained variance in hSAR estimates emphasises the need for improved standardisation in planning, conduct and analysis, and for clear and comprehensive reporting of FFX and HHTIs, to guide evidence-based pandemic preparedness and response efforts for SARS-CoV-2, influenza and future novel respiratory viruses.

7.
BMJ Open ; 12(3): e057741, 2022 03 23.
Article in English | MEDLINE | ID: covidwho-1759370

ABSTRACT

INTRODUCTION: Critical questions remain about COVID-19 vaccine effectiveness (VE) in real-world settings, particularly in middle-income countries. We describe a study protocol to evaluate COVID-19 VE in preventing laboratory-confirmed SARS-CoV-2 infection in health workers (HWs) in Albania, an upper-middle-income country. METHODS AND ANALYSIS: In this 12-month prospective cohort study, we enrolled HWs at three hospitals in Albania. HWs are vaccinated through the routine COVID-19 vaccine campaign. Participants completed a baseline survey about demographics, clinical comorbidities, and infection risk behaviours. Baseline serology samples were also collected and tested against the SARS-CoV-2 spike protein, and respiratory swabs were collected and tested for SARS-CoV-2 by RT-PCR. Participants complete weekly symptom questionnaires and symptomatic participants have a respiratory swab collected, which is tested for SARS-CoV-2. At 3, 6, 9 months and 12 months of the study, serology will be collected and tested for antibodies against the SARS-CoV-2 nucleocapsid protein and spike protein. VE will be estimated using a piecewise proportional hazards model (VE=1-HR). BASELINE DATA: From February to May 2021, 1504 HWs were enrolled. The median age was 44 (range: 22-71) and 78% were female. At enrolment, 72% of participants were seropositive for SARS-CoV-2. 56% of participants were vaccinated with one dose, of whom 98% received their first shot within 4 days of enrolment. All HWs received the Pfizer BNT162b2 mRNA COVID-19 vaccine. ETHICS AND DISSEMINATION: The study protocol and procedures were reviewed and approved by the WHO Ethical Review Board, reference number CERC.0097A, and the Albanian Institute of Public Health Ethical Review Board, reference number 156. All participants have provided written informed consent to participate in this study. The primary results of this study will be published in a peer-reviewed journal at the time of completion. TRIAL REGISTRATION NUMBER: NCT04811391.


Subject(s)
COVID-19 , Viral Vaccines , Adult , Albania/epidemiology , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Vaccines , Female , Health Personnel , Humans , Prospective Studies , SARS-CoV-2 , Spike Glycoprotein, Coronavirus
8.
Int J Infect Dis ; 112: 352-361, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1654550

ABSTRACT

BACKGROUND: The secondary attack rate (SAR) of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was estimated, and the risk factors for infection among members of households with a coronavirus disease 2019 (COVID-19) index case were identified to inform preventive measures. METHODS: Between 3 August and 19 December 2020, a household transmission study was implemented based on a standardized World Health Organization protocol. Laboratory-confirmed cases of SARS-CoV-2 infection were recruited through the federal COVID-19 database. Trained contact tracers interviewed index cases and household members to collect information on demographic, clinical and behavioural factors. Contacts were followed up for 28 days to identify secondary infections. SAR was estimated and odds ratios (OR) were calculated for risk factors for transmission. RESULTS: In total, 383 households and 793 contacts were included in this study. The overall SAR was 17% [95% confidence interval (CI) 14-21]. Contacts had higher risk for infection if the primary case had both cough and runny nose (OR 4.31, 95% CI 1.60-11.63), if the contact was aged 18-49 years (OR 4.67, 95% CI 1.83-11.93), if the contact kissed the primary case (OR 3.16, 95% CI 1.19-8.43), or if the contact shared a meal with the primary case (OR 3.10, 95% CI 1.17-8.27). CONCLUSIONS: These results add to the global literature by providing evidence from a middle-income setting. Standard preventive measures in households with positive cases remain critical to reduce transmission.


Subject(s)
COVID-19 , SARS-CoV-2 , Bosnia and Herzegovina/epidemiology , Contact Tracing , Family Characteristics , Humans , Prospective Studies
9.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-296545

ABSTRACT

Background: COVID-19 case data underestimates infection and immunity, especially in low- and middle-income countries (LMICs). We meta-analyzed standardized SARS-CoV-2 seroprevalence studies to estimate global seroprevalence. Objectives/Methods We conducted a systematic review and meta-analysis, searching MEDLINE, Embase, Web of Science, preprints, and grey literature for SARS-CoV-2 seroprevalence studies aligned with the WHO UNITY protocol published between 2020-01-01 and 2021-10-29. Eligible studies were extracted and critically appraised in duplicate. We meta-analyzed seroprevalence by country and month, pooling to estimate regional and global seroprevalence over time;compared seroprevalence from infection to confirmed cases to estimate under-ascertainment;meta-analyzed differences in seroprevalence between demographic subgroups;and identified national factors associated with seroprevalence using meta-regression. PROSPERO: CRD42020183634. Results We identified 396 full texts reporting 736 distinct seroprevalence studies (41% LMIC), including 355 low/moderate risk of bias studies with national/sub-national scope in further analysis. By April 2021, global SARS-CoV-2 seroprevalence was 26.1%, 95% CI [24.6-27.6%]. Seroprevalence rose steeply in the first half of 2021 due to infection in some regions (e.g., 18.2% to 45.9% in Africa) and vaccination and infection in others (e.g., 11.3% to 57.4% in the Americas high-income countries), but remained low in others (e.g., 0.3% to 1.6% in the Western Pacific). In 2021 Q1, median seroprevalence to case ratios were 1.9:1 in HICs and 61.9:1 in LMICs. Children 0-9 years and adults 60+ were at lower risk of seropositivity than adults 20-29. In a multivariate model using data pre-vaccination, more stringent public health and social measures were associated with lower seroprevalence. Conclusions Global seroprevalence has risen considerably over time and with regional variation, however much of the global population remains susceptible to SARS-CoV-2 infection. True infections far exceed reported COVID-19 cases. Standardized seroprevalence studies are essential to inform COVID-19 control measures, particularly in resource-limited regions.

10.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-296217

ABSTRACT

Seroprevalence surveys are essential to assess the age-specific prevalence of pre-existing cross-reactive antibodies in the population with the emergence of a novel pathogen;to measure population cumulative seroincidence of infection, and to contribute to estimating infection severity. With the emergence of SARS-CoV-2, ECDC and WHO Regional Office for Europe have supported Member States in undertaking standardized population-based SARS-CoV-2 seroprevalence surveys across the WHO European Region. The objective of this study was to undertake a systematic literature review of SARS-CoV-2 population seroprevalence studies undertaken in the WHO European Region to measure pre-existing and cumulative seropositivity prior to the roll out of vaccination programmes. We systematically searched MEDLINE, ELSEVIER and the pre-print servers medRxiv and bioRxiv within the COVID-19 Global literature on coronavirus disease database using a predefined search strategy. We included seroepidemiology studies published before the widespread implementation of COVID-19 vaccination programmes in January 2021 among the general population and blood donors, at national and regional levels. Study risk of bias was assessed using a quality scoring system based on sample size, sampling and testing methodologies. Articles were supplemented with unpublished WHO-supported Unity-aligned seroprevalence studies and other studies reported directly to WHO Regional Office for Europe and ECDC. In total, 111 studies from 26 countries published or conducted between 01/01/2020 and 31/12/2020 across the WHO European Region were included. A significant heterogeneity in implementation was noted across the studies, with a paucity of studies from the east of the Region. Eighty-one (73%) studies were assessed to be of low to medium risk of bias. Overall, SARS-CoV-2 seropositivity prior to widespread community circulation was very low. National seroprevalence estimates after circulation started ranged from 0% to 51.3% (median 2.2% (IQR 0.7-5.2%);n=124), while sub-national estimates ranged from 0% to 52% (median 5.8% (IQR 2.3-12%);n=101), with the highest estimates in areas following widespread local transmission. The review found evidence of low national SARS-CoV-2 seroprevalence (<10%) across the WHO European Region in 2020. The low levels of SARS-CoV-2 antibody in most populations prior to the start of vaccine programmes highlights the critical importance of vaccinating priority groups at risk of severe disease while maintaining reduced levels of transmission to minimize population morbidity and mortality.

11.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-293609

ABSTRACT

Seroprevalence surveys are essential to assess the age-specific prevalence of pre-existing cross-reactive antibodies in the population with the emergence of a novel pathogen;to measure population cumulative seroincidence of infection, and to contribute to estimating infection severity. With the emergence of SARS-CoV-2, ECDC and WHO Regional Office for Europe have supported Member States in undertaking standardized population-based SARS-CoV-2 seroprevalence surveys across the WHO European Region. The objective of this study was to undertake a systematic literature review of SARS-CoV-2 population seroprevalence studies undertaken in the WHO European Region to measure pre-existing and cumulative seropositivity prior to the roll out of vaccination programmes. We systematically searched MEDLINE, ELSEVIER and the pre-print servers medRxiv and bioRxiv within the COVID-19 Global literature on coronavirus disease database using a predefined search strategy. We included seroepidemiology studies published before the widespread implementation of COVID-19 vaccination programmes in January 2021 among the general population and blood donors, at national and regional levels. Study risk of bias was assessed using a quality scoring system based on sample size, sampling and testing methodologies. Articles were supplemented with unpublished WHO-supported Unity-aligned seroprevalence studies and other studies reported directly to WHO Regional Office for Europe and ECDC. In total, 111 studies from 26 countries published or conducted between 01/01/2020 and 31/12/2020 across the WHO European Region were included. A significant heterogeneity in implementation was noted across the studies, with a paucity of studies from the east of the Region. Eighty-one (73%) studies were assessed to be of low to medium risk of bias. Overall, SARS-CoV-2 seropositivity prior to widespread community circulation was very low. National seroprevalence estimates after circulation started ranged from 0% to 51.3% (median 2.2% (IQR 0.7-5.2%);n=124), while sub-national estimates ranged from 0% to 52% (median 5.8% (IQR 2.3-12%);n=101), with the highest estimates in areas following widespread local transmission. The review found evidence of low national SARS-CoV-2 seroprevalence (<10%) across the WHO European Region in 2020. The low levels of SARS-CoV-2 antibody in most populations prior to the start of vaccine programmes highlights the critical importance of vaccinating priority groups at risk of severe disease while maintaining reduced levels of transmission to minimize population morbidity and mortality.

12.
PLoS One ; 16(10): e0259318, 2021.
Article in English | MEDLINE | ID: covidwho-1496537

ABSTRACT

PURPOSE: The purpose of this study was to characterize the nasopharyngeal microbiota of infants with possible and confirmed pertussis compared to healthy controls. METHODS: This prospective study included all infants <1 year with microbiologically confirmed diagnosis of pertussis attended at a University Hospital over a 12-month period. For each confirmed case, up to 2 consecutive patients within the same age range and meeting the clinical case definition of pertussis but testing PCR-negative were included as possible cases. A third group of asymptomatic infants (healthy controls) were also included. Nasopharyngeal microbiota was characterized by sequencing the V3-V4 region of the 16S rRNA gene. Common respiratory DNA/RNA viral co-infection was tested by multiplex PCR. RESULTS: Twelve confirmed cases, 21 possible cases and 9 healthy controls were included. Confirmed whooping cough was primarily driven by detection of Bordetella with no other major changes on nasopharyngeal microbiota. Possible cases had limited abundance or absence of Bordetella and a distinctive microbiota with lower bacterial richness and diversity and higher rates of viral co-infection than both confirmed cases and healthy controls. Bordetella reads determined by 16S rRNA gene sequencing were found in all 12 confirmed cases (100%), 3 out of the 21 possible cases (14.3%) but in any healthy control. CONCLUSION: This study supports the usefulness of 16S rRNA gene sequencing for improved sensitivity on pertussis diagnosis compared to real-time PCR and to understand other microbial changes occurring in the nasopharynx in children <1 year old with suspected whooping cough compared to healthy controls.


Subject(s)
Microbiota , Whooping Cough/microbiology , Bordetella/genetics , Bordetella/isolation & purification , Bordetella/pathogenicity , Case-Control Studies , Female , Humans , Infant , Male , Nasal Cavity/microbiology , Pharynx/microbiology , RNA, Ribosomal, 16S/genetics , Whooping Cough/diagnosis
13.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-291169

ABSTRACT

Background: Claims of influenza vaccination increasing COVID-19 risk are circulating. Within the I-MOVE-COVID-19 primary care multicentre study, we measured the association between 2019–20 influenza vaccination and COVID-19. Methods We conducted a multicentre test-negative case-control study at primary care level, in study sites in five European countries, from March–August 2020. Patients presenting with acute respiratory infection were swabbed, with demographic, 2019–20 influenza vaccination and clinical information documented. Using logistic regression we measured the adjusted odds ratio (aOR), adjusting for study site and age, sex, calendar time, presence of chronic conditions. The main analysis included patients swabbed ≤7 days after onset from the three countries with <15% of missing influenza vaccination. In secondary analyses, we included five countries, using multiple imputation with chained equations to account for missing data. Results We included 257 COVID-19 cases and 1631 controls in the main analysis (three countries). The overall aOR between influenza vaccination and COVID-19 was 0.93 (95% CI: 0.66–1.32). The aOR was 0.92 (95% CI: 0.58–1.46) and 0.92 (95%CI: 0.51–1.67) among those aged 20–59 and ≥60 years, respectively. In secondary analyses, we included 6457 cases and 69272 controls. The imputed aOR was 0.87 (95% CI: 0.79–0.95) among all ages and any delay between swab and symptom onset. Conclusions There was no evidence that COVID-19 cases were more likely to be vaccinated against influenza than controls. Influenza vaccination should be encouraged among target groups for vaccination. I-MOVE-COVID-19 will continue documenting influenza vaccination status in 2020-21, in order to learn about effects of recent influenza vaccination.

14.
Influenza Other Respir Viruses ; 16(1): 7-13, 2022 01.
Article in English | MEDLINE | ID: covidwho-1455561

ABSTRACT

BACKGROUND: The declaration of Coronavirus disease 2019 (COVID-19) as a Public Health Emergency of International Concern (PHEIC) on 30 January 2020 required rapid implementation of early investigations to inform appropriate national and global public health actions. METHODS: The suite of existing pandemic preparedness generic epidemiological early investigation protocols was rapidly adapted for COVID-19, branded the 'UNITY studies' and promoted globally for the implementation of standardized and quality studies. Ten protocols were developed investigating household (HH) transmission, the first few cases (FFX), population seroprevalence (SEROPREV), health facilities transmission (n = 2), vaccine effectiveness (n = 2), pregnancy outcomes and transmission, school transmission, and surface contamination. Implementation was supported by WHO and its partners globally, with emphasis to support building surveillance and research capacities in low- and middle-income countries (LMIC). RESULTS: WHO generic protocols were rapidly developed and published on the WHO website, 5/10 protocols within the first 3 months of the response. As of 30 June 2021, 172 investigations were implemented by 97 countries, of which 62 (64%) were LMIC. The majority of countries implemented population seroprevalence (71 countries) and first few cases/household transmission (37 countries) studies. CONCLUSION: The widespread adoption of UNITY protocols across all WHO regions indicates that they addressed subnational and national needs to support local public health decision-making to prevent and control the pandemic.


Subject(s)
COVID-19 , Pandemics , Humans , Pandemics/prevention & control , SARS-CoV-2 , Seroepidemiologic Studies , World Health Organization
15.
Euro Surveill ; 26(29)2021 07.
Article in English | MEDLINE | ID: covidwho-1323061

ABSTRACT

We measured COVID-19 vaccine effectiveness (VE) against symptomatic SARS-CoV-2 infection at primary care/outpatient level among adults ≥ 65 years old using a multicentre test-negative design in eight European countries. We included 592 SARS-CoV-2 cases and 4,372 test-negative controls in the main analysis. The VE was 62% (95% CI: 45-74) for one dose only and 89% (95% CI: 79-94) for complete vaccination. COVID-19 vaccines provide good protection against COVID-19 presentation at primary care/outpatient level, particularly among fully vaccinated individuals.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Aged , COVID-19 Vaccines , Europe , Humans , Primary Health Care
16.
Vaccine ; 39(30): 4013-4024, 2021 07 05.
Article in English | MEDLINE | ID: covidwho-1253726

ABSTRACT

Phase 3 randomized-controlled trials have provided promising results of COVID-19 vaccine efficacy, ranging from 50 to 95% against symptomatic disease as the primary endpoints, resulting in emergency use authorization/listing for several vaccines. However, given the short duration of follow-up during the clinical trials, strict eligibility criteria, emerging variants of concern, and the changing epidemiology of the pandemic, many questions still remain unanswered regarding vaccine performance. Post-introduction vaccine effectiveness evaluations can help us to understand the vaccine's effect on reducing infection and disease when used in real-world conditions. They can also address important questions that were either not studied or were incompletely studied in the trials and that will inform evolving vaccine policy, including assessment of the duration of effectiveness; effectiveness in key subpopulations, such as the very old or immunocompromised; against severe disease and death due to COVID-19; against emerging SARS-CoV-2 variants of concern; and with different vaccination schedules, such as number of doses and varying dosing intervals. WHO convened an expert panel to develop interim best practice guidance for COVID-19 vaccine effectiveness evaluations. We present a summary of the interim guidance, including discussion of different study designs, priority outcomes to evaluate, potential biases, existing surveillance platforms that can be used, and recommendations for reporting results.


Subject(s)
COVID-19 , Vaccines , COVID-19 Vaccines , Humans , SARS-CoV-2 , World Health Organization
17.
Influenza Other Respir Viruses ; 15(4): 429-438, 2021 07.
Article in English | MEDLINE | ID: covidwho-1042709

ABSTRACT

BACKGROUND: Claims of influenza vaccination increasing COVID-19 risk are circulating. Within the I-MOVE-COVID-19 primary care multicentre study, we measured the association between 2019-20 influenza vaccination and COVID-19. METHODS: We conducted a multicentre test-negative case-control study at primary care level, in study sites in five European countries, from March to August 2020. Patients presenting with acute respiratory infection were swabbed, with demographic, 2019-20 influenza vaccination and clinical information documented. Using logistic regression, we measured the adjusted odds ratio (aOR), adjusting for study site and age, sex, calendar time, presence of chronic conditions. The main analysis included patients swabbed ≤7 days after onset from the three countries with <15% of missing influenza vaccination. In secondary analyses, we included five countries, using multiple imputation with chained equations to account for missing data. RESULTS: We included 257 COVID-19 cases and 1631 controls in the main analysis (three countries). The overall aOR between influenza vaccination and COVID-19 was 0.93 (95% CI: 0.66-1.32). The aOR was 0.92 (95% CI: 0.58-1.46) and 0.92 (95% CI: 0.51-1.67) among those aged 20-59 and ≥60 years, respectively. In secondary analyses, we included 6457 cases and 69 272 controls. The imputed aOR was 0.87 (95% CI: 0.79-0.95) among all ages and any delay between swab and symptom onset. CONCLUSIONS: There was no evidence that COVID-19 cases were more likely to be vaccinated against influenza than controls. Influenza vaccination should be encouraged among target groups for vaccination. I-MOVE-COVID-19 will continue documenting influenza vaccination status in 2020-21, in order to learn about effects of recent influenza vaccination.


Subject(s)
COVID-19/epidemiology , Influenza Vaccines/administration & dosage , Influenza, Human/prevention & control , Orthomyxoviridae/immunology , Vaccination/statistics & numerical data , COVID-19/diagnosis , Case-Control Studies , Europe/epidemiology , Female , Humans , Influenza, Human/diagnosis , Influenza, Human/epidemiology , Logistic Models , Male , Odds Ratio , Primary Health Care/organization & administration , Primary Health Care/statistics & numerical data , Respiratory Tract Infections/diagnosis , Respiratory Tract Infections/epidemiology , Respiratory Tract Infections/prevention & control , SARS-CoV-2
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